Enter the daily flow and the absorption rate into the calculator to determine the required septic field size. This calculator helps in planning and designing a septic system for residential or commercial properties.
Septic Field Size Formula
The following formula is used to calculate the septic field size.
SFS = DF / AR
Variables:
- SFS is the septic field size (square feet)
- DF is the daily flow of wastewater (gallons per day)
- AR is the absorption rate of the soil (gallons per day per square foot)
To calculate the septic field size, divide the daily flow of wastewater by the absorption rate of the soil.
What is a Septic Field Size?
Septic field size refers to the area of land required for the installation of a septic drain field, which is a component of a septic system where effluent from the septic tank is absorbed into the soil. The size of the septic field is crucial for the proper treatment of wastewater and to prevent system failure. It is determined by the daily flow of wastewater and the soil’s absorption rate, which varies depending on soil type and environmental conditions.
How to Calculate Septic Field Size?
The following steps outline how to calculate the Septic Field Size.
- First, determine the daily flow of wastewater (DF) in gallons per day.
- Next, determine the absorption rate of the soil (AR) in gallons per day per square foot.
- Next, gather the formula from above = SFS = DF / AR.
- Finally, calculate the Septic Field Size (SFS) in square feet.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
daily flow of wastewater (DF) = 500 gallons per day
absorption rate of the soil (AR) = 0.4 gallons per day per square foot